Estimating breast specimen volume from weight and radiological density
Research type
Research Study
Full title
DEVELOPMENT OF A NEW APPROACH TO MEASURE THE VOLUME OF BREAST TISSUE REMOVED DURING WIDE LOCAL EXCISION USING SPECIMEN WEIGHT AND MAMMOGRAPHIC DENSITY
IRAS ID
325661
Contact name
Emanuele Garreffa
Contact email
Sponsor organisation
University Hospitals of Derby and Burton NHS Foundation Trust
ISRCTN Number
ISRCTN15283352
Clinicaltrials.gov Identifier
ISRCTN registry, ISRCTN15283352
Duration of Study in the UK
1 years, 2 months, 30 days
Research summary
Summary of Research
In women who do not wish mastectomy, breast conserving surgery (cancerous lump removed together with a rim of healthy tissue) is performed. This is followed by radiation treatment to prevent the cancer coming back. The cancer area may also be treated with extra radiation (boost). In women with smaller breasts and larger breast cancer, some skin and fat from outside the breast area can be used to fill the surgical gap to maintain breast shape and volume. This surgery, however, can make the target area for the radiation boost more difficult to identify. A precise estimate of the volume of removed tissue could be used to confirm that the right area has been identified and ensure that the boost target is neither too large nor too small.
Breasts are essentially made of two components: fatty tissue, which is lighter and stays afloat if put in water, and true breast tissue, which is heavier and sinks in water. Women's breasts contain a mixture of fatty tissue and breast tissue, with one or the other being more prominent. As a result of this, the weight of breast tissue removed during breast cancer surgery will vary among women. Therefore, simply using specimen weight cannot provide an accurate estimate of its volume as fatty specimens would be lighter than those mostly containing breast tissue, even though they have the same volume.
We will develop a method to estimate the removed breast volume using the removed tissue x-ray appearance (fatty or dense) and weight. We will also measure the volume with water displacement (a precise but more complex and time-consuming technique) and compare it against our technique. If proven to be accurate, this quick and simple technique will help to identify the right area to boost and could lead to develop a better boost technique.Summary of Results
What was the study about?
This study aimed to understand how accurately the size (volume) of breast tissue removed during surgery can be estimated. We wanted to find out whether a new calculation method could estimate tissue volume more accurately than the method currently used in clinical practice. This matters because accurate volume estimates can influence treatment decisions and help ensure patients receive the most appropriate care.What did we do?
We studied breast tissue samples from women undergoing wide local excision surgery for breast cancer. Tissue samples were collected as part of routine care and no additional procedures were required. We measured the actual volume of the tissue samples and compared these measurements with volumes estimated using the current method and a new method developed using study data. We also looked at whether factors such as tissue weight and density could improve volume estimates.What did we find?
We found that when compared using the complete dataset the new (phase 1) calculation method was no more accurate than the method already in use. Both methods tended to overestimate or underestimate tissue volume for many samples, and only around one quarter of samples were estimated accurately by either method. Overall, the new method did not provide a meaningful improvement compared to current practice.
An additional analysis was undertaken in which estimate of the tissue sample densities were included with the other explanatory variables included in the phase 1 analysis. This also failed to produce more accurate estimates than the current method.
However, the accuracy of the estimation methods appears to be related to the weight of the tissue sample. For samples weighing between 2 and 17g, the method developed in phase 1 (phase1 method) was inclined to be more accurate than the current method. For samples weighing more than 37g the current method tended to be more accurate. For samples between 18 and 37g it was unclear which estimation method produced the most accurate estimates. Tissue sample volume estimates developed for a planned sensitivity analysis and the estimates from the additional analysis described above did not consistently offer more accurate estimates than either the current or the phase 1 methods.What does this mean?
These results suggest that simply changing the calculation method is unlikely to improve how tissue volume is estimated during surgery. However, utilising a combination of estimation methods based on the sample weights may improve the tissue volume estimates, especially for patients with relatively low- or high-weight samples.What happens next?
Unfortunately, none of the methods investigate in this study has been found to be significantly more accurate than the currently used method. The findings will be shared through a scientific publication in line with local policy to ensure that other researchers are aware of these results.REC name
London - Fulham Research Ethics Committee
REC reference
23/PR/0775
Date of REC Opinion
3 Aug 2023
REC opinion
Further Information Favourable Opinion